The present invention relates to the technology to reproduce the musical pieces recorded in different formats such as MIDI (Musical Instrument Digital Interface: registered trade mark) and MP3 (MPEG-1 Audio Layer-III), for example, from the middle of the musical piece in a synchronized state.
The MIDI standard is well known as the standard to provide the reproducing information, and the MP3 format is often used as one of data compression algorithms to record the music. The former is often utilized in the karaoke system (see Patent Literature 1, for example). In recent years, the proposal that intends to use together the musical piece data in the MIDI format (referred to as “MIDI data” hereinafter) and the music data in the MP3 format (referred to as “MP3 data” hereinafter) in the applications suitable to respective characteristics is announced. For example, because the MP3 data can realize the real quality of sound with reality rather than the MIDI data, such MP3 data are used to reproduce a chorus sound or a guide vocal (a vocal sound of the human voice) which requires such characteristic, or a performance of the musical instrument with a distinctive feature, or the like, whereas the MIDI data are used to reproduce an automatic accompaniment, a guide melody, or the like, and others. Here, the guide vocal and the guide melody are that they are reproduced with the accompaniment to permit the singer to sense the primary vocal and melody and sing the song readily.    Patent Literature 1; JP-A-10-11097
Meanwhile, sometimes the music piece reproducing system such as the karaoke system must reproduce the musical piece from the middle of the musical piece. For example, there is the case where the musical piece is reproduced again from the position in which the fast-forward reproducing or the rewind is ended. However, when the operator tries to reproduce the musical piece composed of both the MIDI data and the MP3 data described above from the middle of the musical piece, there existed the problem described in the following.
FIG. 9 is a view showing such a behavior that the MIDI part and the MP3 part are reproduced on a time-series basis. In the MIDI part, the position in which the reproducing is started in the middle of the musical piece can be decided in unit of 1 (ms). Therefore, if the start of the reproducing is instructed when just 25 minutes lapsed after the musical piece is started, for example, the MIDI part in the hatched area is reproduced from the timing indicated with an arrow in FIG. 9.
In contrast, the MP3 data has a data structure in which a plurality of frames in unit of 36 (ms), for example, are connected in series, and thus the musical piece can be reproduced merely in this frame unit. As a result, if the operator tries to start the reproducing at the timing when just 25 minutes lapsed after the musical piece is started, as described above, the musical piece cannot be reproduced from that timing unless such timing coincides accidentally with the head portion of the frame. In such case, the reproducing system cannot but reproduce the musical piece from the head portion of the frame (indicated with a solid-line arrow in FIG. 9) subsequent to the timing (indicated with a dashed-line arrow) at which the musical piece is essentially reproduced. In other words, since the reproducing of the MP3 part is started somewhat later than the reproducing of the MIDI part, it is possible that the listener hears such reproducing as the artificial performance.